[Asterisk-Users] 5,000 concurrent calls system rollout question

[Boris Bakchiev]

>I guess I just assumed that that the connection to asterisk would have
>to be IP since it is absolutely impossible to connect ~208 T1s directly
>to a single asterisk server. You would have to use an external media
>gateway. I am not aware of any 200x T1 or 8x T3 cards for asterisk :)


Not necessarily.

Granted that you will not be able to have have that many T1's on one
system but if the load is spread across multiple "Asterisk Media
converters" you should be able to do anything and scale your system much
better.

Lets consider for example the following scenario:

------------------       ------------------
|   * Media      |       |   * Media      |
|    server      |       |    server      |
|   2x TE406P    |       |   2x TE406P    |
------------------       ------------------
               |            |
             -------------------
             |     Main *      |
             |     server      |
             |                 |
             -------------------
               |            |
------------------       ------------------
|   * Media      |       |   * Media      |
|    server      |       |    server      |
|   2x TE406P    |       |   2x TE406P    |
------------------       ------------------


This will let you serve 192 channels per media server.
Media servers will only need to convert PRI<->IP so a cheap DIY Dual
Core Xeon MP with 4MB cache would be more then enough to
process/compress 196 channels in/out of 2 TE406P's. Also media servers
do not need much RAM, hard drives and can run from flash cards.
My preference would be convert all the traffic coming out of media
servers to G.729 and IAX2 trunk it to main server. IAX2 trunking will
save you MANY interrupts and will improve your bandwidth utilisation
between Media and Main servers.

With this setup you can run Media and Main servers on private gigabit
network which would be more then enough to handle IAX2 trunked G.729
traffic from media servers. Network redundancy can easily be achieved
between Media and Main servers by adding NIC's to each and using many
known techniques (bonding, routing, VRRP, etc, etc).

The Main Asterisk server can be setup with load balancing/failover.
Media servers will need to be aware of this.

The good thing in the setup like this is that its easy to scale up when
needed, you're not exposed of loosing all of your T1's if one of media
servers fail, you can easily add more T1's in your setup.

The Main server would need a quad gigabit card (intel is a good choice)
and since it would not be hampered by Zaptel traffic and it would not
need to do any transcoding (except for odd voicemail usage, that could
be send to another server) you could use 2xDual Core Xeons. A separate
dual port (for redundancy) gigabit card would be used to serve SIP
clients.

We're working with one of the ISP's on testing and perhaps implementing
this setup for them.

This setup is considerably cheaper then $1M proposed Cisco setup and can
be made as reliable as Cisco solution is.
Please don't get me wrong, if I'd have $1M-$5M to spare would go for
Cisco.
But most of us don't have that much money and if we would, we would
never be reading any messages on asterisk-users.

Asterisk can be made as reliable and scales as good if not better then
any Cisco solution and the fraction of the cost.

Now imagine all of this with the new DS3000P in media servers!

All hail Asterisk! :)